Right now in the US there is practically no enforceable legal standard for towing whatever one wants with whatever they feel like. TV rating don't factor, driver experience doesn't matter. For all our sake, and especially now as record number of people are hitting the roads with RV's we might think about having some legal standards.
You've been reading to many rv websites. :)
Every state has enforceable weight restrictions for all vehicle on the road. Take the time and find out what your state uses to enforce vehicle weight laws. Make the effort and be informed and you will find we have plenty of codes on the books for overweight vehicles of all sizes
Now if your talking about making numbers like tow ratings.....mfg GVWR...mfg GCWR....tire placard payload numbers....truck mfg payload/etc a legal standard as you call it then fed laws will have to be changed. Once fed weight laws change then states have to adopt the changes.
Feds have said in a rules change NPRM ;
NPRM DOT Docket No. NHTSA-2007-0040
RIN 2127-AJ57
page 68454
(snipped for length)
NHTSA's Office of Vehicle
Safety Compliance (OVSC) enforces current NHTSA regulations and will
enforce the requirements in this final rule when it becomes effective.
We note that actual RV crash data specific to crashes where an
overloaded RV is a contributing factor are rare.
Agree with one poster about just another the sky is falling type thread with no specific weight numbers for a specific vehicle but just a condemnation on others that don't use numbers he thinks should be used.